Spring counterbalanced arm assemblies have been provided in the prior art for supporting electric lamp heads. Such assemblies usually incorporate external tension springs, and those which have been provided which are free from external springs have, for the most part, had substantial deficiencies in use. For example, some have not functioned properly while others are too complicated or costly or have limited useful life. The counterbalanced arm assembly with external coil tension springs have operated satisfactorily, however, the springs tend to collect dust and are difficult to keep clean. The counterbalanced arm assemblies with external springs are usually provided with two parallelogram arm assemblies, the lower of which is mounted at its bottom end upon a swivel point, and hinged at its other end to the upper end. The lamp head is mounted on the other end of the upper end, and is thereby provided with a universal joint mounting. Spring tension forces support the lamp assembly so that it can be moved throughout a wide range both vertically and horizontally.
An objective of the present invention is to provide a counterbalanced arm assembly which has all the features of the external spring assembly insofar as operation, cost and long life is concerned, but which is equipped with innersprings, so that the problems of external springs are resolved.
Accordingly, the principal objectives of the present invention are to provide an improved spring counterbalanced arm assembly for an electric lamp head, or the like, which is simple and inexpensive to construct, which is easy to adjust to any desired position and inclination of the lamp head without burning the fingers of the operator, and which is trouble-free in its operation.